1. Field of the Invention
The present invention relates to a structure of an oil pan for storing an engine oil; and an oil pan separator, disposed within the oil pan, for separating the inside of the oil pan into main and sub chambers.
2. Related Background Art
Engine oils have conventionally been employed for lubricating/cooling engines. Such an engine oil is stored in an oil pan disposed under an engine, and is circulated through individual parts of the engine by an oil pump. The engine oil circulated through the individual parts of the engine drops into the oil pan thereunder. The engine oil dropped into the oil pan is recirculated through the individual parts of the engine by the oil pump. During this period, the engine oil receives heat from the individual parts of the engine and cools them. The engine oil also acts to form oil films in the individual parts of the engine, thereby promoting lubrications among the parts, preventing the parts from oxidizing, and so forth.
Immediately after a cold start, the engine oil stored in the oil pan is cold and has a high viscosity, whereby it is not in a state suitable for circulating through the individual parts of the engine and lubricating them. Therefore, immediately after the cold start, the engine oil is desired to raise its temperature as soon as possible, so as to attain a state having an appropriate viscosity. To this aim, it has already been proposed to divide an oil pan into a plurality of sections, so as to prepare a state where the engine oil within one of the sections is likely to circulate immediately after the cold start, and heat the engine oil within this section earlier so as to attain a favorable state (e.g., Japanese Patent Application Laid-Open No. HEI 6-17633).
However, there have been demands for improvements by which the temperature of engine oil rises earlier. An early temperature rise in the engine oil also contributes to ameliorating the fuel consumption by lowering frictions earlier, thus being desired for improvement in view of strong demands for amelioration of fuel consumption in recent years as well. Also, improvements in terms of manufacture have been desired in conventional methods in which, for example, metal sheets are welded to the inside of the oil pan in order to divide it into a plurality of sections.
Therefore, it is an object of the present invention to provide an oil pan structure which can raise the temperature of an engine oil more effectively, and an oil pan separator which can suitably be used in this structure.
The oil pan structure of the present invention comprises an oil pan separator, disposed within an oil pan, for separating a main chamber provided with a suction port disposed therewithin and a sub chamber provided with no suction port from each other, the oil pan separator having a recess forming the main chamber, the main chamber communicating with the inside of an engine block, the recess being formed with a communication hole for communicating the main and sub chambers to each other. This enables the engine oil within the main chamber to raise its temperature earlier so as to be sent to individual parts of the engine, whereby optimal lubrications can be achieved in the individual parts of the engine at an early stage. As a result, earlier stabilization of engine operations, improvement in exhaust cleaning performances, amelioration in fuel consumption performances, and the like can be achieved.
Preferably, the sub chamber is formed so as to surround the main chamber as a whole, whereas the outer face of a bottom part of the oil pan separator and the inner face of a bottom part of the oil pan are not in contact with each other. Here, it is also preferred that a damping material be disposed between the bottom part of the oil pan separator and the oil pan. Here, it will also be preferred if an outer periphery of the oil pan separator is secured by being held between divided parts of the engine block or between the engine block and the oil pan.
Preferably, the oil pan has a foamed resin layer on the inner surface side thereof, whereas the foamed resin layer has a higher density in a surface coming into contact with an oil and a lower density on the inside thereof. Here, it is also preferred that the oil pan separator be formed from a synthetic resin. Here, it will also be preferred if the oil pan separator is formed from a foamed resin having a higher density in each surface coming into contact with the oil and a lower density on the inside thereof.
Preferably, an oil suction pipe having the suction port at an end part thereof is integrally formed with the oil pan separator. Here, it is also preferred that the recess of the oil pan separator have a double-wall structure.
It is preferred that a lid be disposed on the upper side of the main chamber, an opening for introducing an engine oil into the main chamber being formed in the lid at a center thereof, the lid tilting downward in an outward direction from the opening.
Preferably, at least one first communication hole is formed on the upper side of a side wall of the main chamber, at least one second communication hole is formed on the lower side of the side wall of the main chamber, each first communication hole has an opening area larger than that of each second communication hole, and the first and second communication holes are formed at respective positions substantially opposing each other with respect to the center of the main chamber. It will be preferred if such a communication hole for communicating the main and sub chambers to each other is a burring hole or a louver hole.
Preferably, the oil pan structure comprises a heat exchanger for exchanging heat between engine cooling water and the engine oil, a heat storage tank for storing the engine cooling water after warming up, and heat-accumulated water supplying means for supplying the heat exchanger with the engine cooling water stored in the heat storage tank immediately after a cold start. Alternatively, it is preferred that the oil pan structure comprise a heat storage tank for storing the engine tank after warming up, and heat-accumulated oil supplying means for supplying the main chamber with the engine oil stored in the heat storage tank immediately after a cold start.
The oil pan separator of the present invention is disposed in an oil pan of an internal combustion engine, and separates a space within the oil pan into a main chamber provided with a suction part (suction port) of an oil pump and a sub chamber provided with no suction part. Here, the oil pan separator has a main chamber constructing part (recess) formed from a heat-insulating sheet material having a heat-insulating property and recessed so as to be able to store a lubrication oil, whereas the main chamber constructing part is accommodated in the oil pan. A space within the main chamber constructing part constitutes the main chamber, whereas a portion of the part constituting a wall of the main chamber constructing part separates the main and sub chambers from each other.
Preferably, the oil pan separator is integrally formed with an oil pan gasket part interposed between a cylinder block of the internal combustion engine and the oil pan. Preferably, the heat-insulating sheet material is one in which both sides of a metal sheet are coated with a compound containing a heat-resistant nonmetal fiber other than asbestos, a filler, and an elastomer. Preferably, a portion separating the main and sub chambers from each other in the part constituting the wall of the main chamber constructing part is formed with an opening (communication hole) communicating the main and sub chambers to each other, whereas a nonwoven or net adapted to filter a lubrication oil therethrough is attached to the opening.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.